Installing a Ceiling Fan Box

Ceiling fans are heavy and they vibrate. A fan installed on a standard ceiling fixture box could come loose and perhaps crash to the floor.

The first step in adding a ceiling fan is to inspect the existing electrical box. Shut off power to the circuit. Test to confirm that the power is off and remove the existing ceiling fixture.

Most building codes require ceiling fans to be mounted on special fan-rated boxes, which are made of metal or strong plastic and have deep-threaded holes for the mounting screws. The box must be mounted firmly, either by attaching it directly to a framing member or by using a fan-rated brace.

Replacing a ceiling box is a messy job. Work carefully to avoid cutting through wires hidden in the ceiling.

Use a knife (not a saw) to cut through the drywall or plaster around the old box. The box is probably attached to a joist with screws or two horizontally driven nails. Force the box loose by hammering a 2X4 into it.

Insert a flat pry bar between the box and the joist. Pry the box away from the joist. You may need to pry out a staple anchoring the cable to the joist. Work carefully to avoid unnecessary damage to the ceiling.

Pry out the box's mounting nails and pull the box down from the ceiling. Disconnect the cable from the box. The box shown has a slot that the cable slides through; pry the tab and pull the cable out. If the box has a cable clamp, remove the locknut.

If a box is too firmly mounted to be knocked free, cut a hole into the ceiling just large enough so you can see the mounting nails and the cable. Carefully cut through the nails with a reciprocating saw.